UserName = "admin"
Password = "123456"
Exit = "exit"

while True:
    userName = input("请输入用户名：")
    # 如果用户输入的用户名为exit，就退出程序
    if Exit == userName:
        print("正在退出程序 ^_^ ...")
        break
    password = input("请输入密码：")
    # 用户名和密码都正确，成功登录，并退出
    if UserName == userName and Password == password:
        print("登录成功！")
        break
    # 否则，重新登录
    else:
        print("用户名或密码错误！")
        print('-' * 21)
